> ## Documentation Index
> Fetch the complete documentation index at: https://docs.delphimarkets.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> API keys, rate limits, and error handling

All API requests require an API key passed in the `X-API-Key` header.

```bash theme={"theme":"one-dark-pro"}
curl -X GET 'https://api.delphiterminal.co/api/v1/klsi/markets' \
  -H 'X-API-Key: dphi_live_your_key_here'
```

## API key types

| Type           | Duration   | Rate Limit  | How to Get                                 |
| -------------- | ---------- | ----------- | ------------------------------------------ |
| Test key       | 10 minutes | 60 req/min  | `POST /api/v1/test-key` (no auth required) |
| Production key | Permanent  | 300 req/min | [Contact us](https://delphimarkets.com)    |

Test keys are useful for exploring the API and building prototypes. For production workloads, request a permanent key.

## Rate limits

Requests are rate-limited per API key:

* **Test keys**: 60 requests per minute
* **Production keys**: 300 requests per minute

When you exceed the limit, you'll receive a `429 Too Many Requests` response. Wait and retry.

## Error codes

All errors return JSON with an `error` field:

```json theme={"theme":"one-dark-pro"}
{"error": "invalid api key format"}
```

| Code  | Meaning                                        |
| ----- | ---------------------------------------------- |
| `400` | Bad Request — invalid parameters               |
| `401` | Unauthorized — missing or invalid API key      |
| `404` | Not Found — resource doesn't exist             |
| `429` | Too Many Requests — rate limit exceeded        |
| `500` | Server Error — something went wrong on our end |

## Unauthenticated endpoints

A few endpoints don't require an API key:

* `POST /api/v1/test-key` — generate a test key
* `GET /health` — health check
* `POST /api/v1/auth/signup` — create a user account
* `POST /api/v1/auth/login` — authenticate and get a session token